• Molecules and Cells
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• v.41 no.7
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• pp.695-702
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• 2018

The inner ear is a complex sensory organ responsible for hearing and balance. Formation of the inner ear is dependent on tight regulation of spatial and temporal expression of genes that direct a series of developmental processes. Recently, epigenetic regulation has emerged as a crucial regulator of the development of various organs. However, what roles higher-order chromatin organization and its regulator molecules play in inner ear development are unclear. CCCTC-binding factor (CTCF) is a highly conserved 11-zinc finger protein that regulates the three-dimensional architecture of chromatin, and is involved in various gene regulation processes. To delineate the role of CTCF in inner ear development, the present study investigated inner ear-specific Ctcf knockout mouse embryos (Pax2-Cre; $Ctcf^{fl/fl}$). The loss of Ctcf resulted in multiple defects of inner ear development and severely compromised otic neurogenesis, which was partly due to a loss of Neurog1 expression. Furthermore, reduced Neurog1 gene expression by CTCF knockdown was found to be associated with changes in histone modification at the gene's promoter, as well as its upstream enhancer. The results of the present study demonstrate that CTCF plays an essential role in otic neurogenesis by modulating histone modification in the Neurog1 locus.

• Journal of Climate Change Research
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• v.5 no.4
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• pp.331-338
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• 2014

The continued efforts to reduce GHG emission by international cooperation and each country are in progress. As part of these efforts, Korea's ETS is enforced in 2015. This was the time to make strategies for each company to respond Korea's ETS. This study was performed to suggest a draft of basic strategies for electronic component industry in current Korea's ETS stage are as follows; - Analyzing the nature of electronic component industry - Identifying needs for corresponding ETS of electronic component industry - Analyzing basic countermeasures for each stage of ETS - Suggesting drafts of basic strategies for electronic component industry in current Korea's ETS stage The result of this study, the current stage of Korea's ETS is moving from implementation of the scheme become determined and prepare the minimum corresponding to direct corresponding to the regulation and market change. Electronic component industry has many GHG emission growth(or change) factor, and it will be make electronic component industry as a buyer when Korea's ETS is enforced. Korea's ETS will be clearly act as a regulation rather than new business for electronic component industry. Therefore, identifying the Korea's ETS as a regulation is resonable strategy for corresponding the scheme. The basic strategies of electronic component industry th responding Korea's ETS are as follows; - Building internal organization and decision-making system before enforcement the Korea's ETS - Establishing internal basic corresponding strategies according to carbon price forecast scenarios - Considering the energy consumption and GHG emissions in design phase and preparing the global ETS market in mid or long term.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.307-314
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• 2019

The study examined the mediating effect of emotional dysregulation on the relationship between care worker's job stress and mental health. The Geriatric Caregiver's Job Stress Questionnaire, Difficulties in Emotion Regulation Scale, and The Symptom Check-List-90-R were administered to 154 care workers. Through the hierarchical regression analysis, direct interrelationship among job stress, emotional dysregulation, and mental health was examined. Furthermore, the statistical significance of mediating effect of emotional dysregulation on the relationship between job stress and mental health was tested through the bootstrapping. The result showed that the lack of emotional clarity and the limited access to emotion regulation strategies appeared to have a complete mediation effect on the relationship between job stress and mental health. That meant the necessity of adaptive emotional regulation in dealing with mental health problem elicited by job stress.

• Progress in Medical Physics
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• v.21 no.3
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• pp.239-245
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• 2010

The purpose of this study is to comprehensively compare and evaluate the characteristics of image quality for digital mammography systems which use a direct and indirect conversion detector. Three key metrics of image quality were evaluated for the direct and indirect conversion detector, the modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE), which describe the resolution, noise, and signal to noise performance, respectively. DQE was calculated by using a edge phantom for MTF determination according to IEC 62220-1-2 regulation. The contrast to noise ratio (CNR) was evaluated according to guidelines offered by the Korean Institute for Accreditation of Medical Image (KIAMI). As a result, the higher MTF and DQE was measured with direct conversion detector compared to indirect conversion detector all over spatial frequency. When the average glandular dose (AGD) was the same, direct conversion detector showed higher CNR value. The direct conversion detector which has higher DQE value all over spatial frequency would provide the potential benefits for both improved image quality and lower patient dose in digital mammography system.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.137-148
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• 2002

Direct Torque Control(DTC) is considered to be an useful control scheme of high performance induction motor drives because the scheme provides a quick torque response without requiring the complex field-orientation block and inner current regulation loop. Among a few drawbacks of the conventional DTC scheme, large current harmonics due to flux drooping phenomenon in a low speed range may be the major difficulty In order to remove the difficulty, a fuzzy variable switching sector scheme and its real-time implementation algorithm are proposed in this paper. A DSP based control board is designed for the Induction motor drives with the DTC scheme including the fuzzy switching sector algorithm. Simulation and experimental results show the effectiveness of the proposed scheme.

• Journal of IKEEE
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• v.20 no.2
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• pp.200-204
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• 2016

In this paper, we have estimated the performance of an overflow valve for EURO type CRDI(common rail direct injection) engine. In order to implement the overflow valve with friendly circumstance, it is necessity for considering spring load. Especially, the performance evaluation of diesel car with accuracy control will be considered a mileage improvement and circumstance regulation. In order to evaluate the performance of overflow valve, The leak test system checks the pressure, switching time and operating time under 3.0 bar below 100 cc, 3.3 bar among 150 cc and 200 cc, finally 4.0 bar upper 250 cc.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.89-99
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• 2017

The purpose of this study is to analyze safety and health managers' perceptual maps on the effective educational contents and its methods of workplace safety and health education. Self-administered survey was successfully conducted to 582 workers who were 339 in manufacturing, 68 in construction, and 175 in service & others by industry classification. Survey sites were recruited based on business size, incidence of occupational accident, and compliance of workplace safety and health education regulation. Questionnaire included personal factors, workplace factors, and needs of safety and health education at work. Male workers were 85.3% and more than 50% were in their 30s and had university education. Overall needs of educational contents and its methods were greater in manufacturing and services than construction. Two dimensional properties of effective educational contents perceived were 'knowledge structure' which divided to safety and health, and 'behavior outcomes' which divided to indirect and direct. Two dimensional properties of educational methods were 'class activity' which divided to experience-based and verbal-based and 'class participation' which divided to passive and active. Effective educational contents and its methods perceived by safety and health managers commonly included the characteristics of direct, case-based, and participation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.232-239
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• 2015

Faced with unbalanced grid operation mode, the high voltage direct current (HVDC) based on voltage source converter (VSC) can be properly controlled by a dual current control scheme. For the modular multilevel converter (MMC) controlling the AC side current is able to limit the arm current which flows along the IGBT of submodule (SM) to rated current. However the limitation of the arm current results in leaving the control range of active power at MMC confined to below the rated capacity. As a result, limiting the arm current causes the problem that the DC side voltage of the HVDC can not be controlled to the reference value since MMC HVDC adjusts the DC side voltage through the active power. In this paper, we propose the algorithm adjusting the active powers of both MMCs to resolve the problem. The back-to-back MMC HVDC applying the algorithm is modeled by PSCAD/EMTDC to verify the algorithm.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.24-30
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• 2004

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthened. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, there is trade off between output and NOx in a HCCI engine. In this study, output and emission characteristics for a gasoline direct injection type HCCI engine were investigated to clarify the effects of intake air temperature, injection time and mixture formation. From these experiments, we found that the smoke was not produced when the fuel was injected earlier than BTDC 90$^{\circ}$. In addition, the output was increased because of delay of ignition time and NOx emission was decreased because of homogeneous charge of first injection in case of split injection.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.78-85
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• 2000

This study is to develop the diesel engine which has 6 cylinder natural aspiration direct injection type of 7.4$\ell$ with high performance, low emissions and low fuel consumption Finally the developed engine meets Korean `98 exhaust emission regulation for the city bus of heavy duty diesel engine by optimizing the various combustion parameters affecting performance and exhaust emissions. Combustion parameters are the swirl ratio of intake ports, the profile of injection pump`s cam affecting injection pressure, the design features of piston bowl of injection pump`s cam affecting injection pressure, the design features of piston bowl of combustion chamber and injector`s hole size. Through experimental analysis, various combustion parameters are optimized and the results are as follows; the swirl ratio is 2.20, the profile of injection pump`s cam is concave and re-entrant ratio, inner diameter of piston bowl and hole diameter of injector is 0.88,$\psi$64.0mm and $\psi$0.25mm respectively.